Question

I would like to remove all occurrences of a given value from within a list of lists. For example,
input:

'a' ["abc", "bc", "aa"] 

output:

 ["bc", "bc", ""]

so far:

remove :: Eq a => a -> [[a ]] -> [[a ]]
remove y xs = filter(\x -> x/= y) xs

I’m getting an error, thank you in advance.

Answer 1

You need to map over the outer lists.

remove y xs = map (filter(\x -> x/= y)) xs

You don’t actually need a lambda here, nicer:

remove y xs = map (filter(/=y)) xs